r.viewshed: fix CodeQL warnings

Warnings on comparison of narrow type with wide type in loop condition.

raster/r.viewshed/grass.cpp

@@ -210,6 +210,8 @@ size_t init_event_list_in_memory(AEvent *eventList, char *rastName,
     G_SURFACE_T **inrast;
     int nrows = Rast_window_rows();
     int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
 
     inrast = (G_SURFACE_T **)G_malloc(3 * sizeof(G_SURFACE_T *));
     assert(inrast);
@@ -238,7 +240,7 @@ size_t init_event_list_in_memory(AEvent *eventList, char *rastName,
     Rast_get_row(infd, inrast[2], 0, data_type);
 
     e.angle = -1;
-    for (i = 0; i < nrows; i++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
         /*read in the raster row */
 
         G_SURFACE_T *tmprast = inrast[0];
@@ -254,7 +256,7 @@ size_t init_event_list_in_memory(AEvent *eventList, char *rastName,
         G_percent(i, nrows, 2);
 
         /*fill event list with events from this row */
-        for (j = 0; j < Rast_window_cols(); j++) {
+        for (j = 0; j < (dimensionType)ncols; j++) {
             e.row = i;
             e.col = j;
 
@@ -431,6 +433,8 @@ AMI_STREAM<AEvent> *init_event_list(char *rastName, Viewpoint *vp,
     G_SURFACE_T **inrast;
     int nrows = Rast_window_rows();
     int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
 
     inrast = (G_SURFACE_T **)G_malloc(3 * sizeof(G_SURFACE_T *));
     assert(inrast);
@@ -456,7 +460,7 @@ AMI_STREAM<AEvent> *init_event_list(char *rastName, Viewpoint *vp,
     e.angle = -1;
 
     /*start scanning through the grid */
-    for (i = 0; i < nrows; i++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
 
         G_percent(i, nrows, 2);
 
@@ -473,7 +477,7 @@ AMI_STREAM<AEvent> *init_event_list(char *rastName, Viewpoint *vp,
             Rast_set_null_value(inrast[2], ncols, data_type);
 
         /*fill event list with events from this row */
-        for (j = 0; j < ncols; j++) {
+        for (j = 0; j < (dimensionType)ncols; j++) {
 
             e.row = i;
             e.col = j;
@@ -627,11 +631,16 @@ void save_grid_to_GRASS(Grid *grid, char *filename, RASTER_MAP_TYPE type,
     outrast = Rast_allocate_buf(type);
     assert(outrast);
 
+    int nrows = Rast_window_rows();
+    int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
+
     dimensionType i, j;
 
-    for (i = 0; i < Rast_window_rows(); i++) {
-        G_percent(i, Rast_window_rows(), 5);
-        for (j = 0; j < Rast_window_cols(); j++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
+        G_percent(i, nrows, 5);
+        for (j = 0; j < (dimensionType)ncols; j++) {
             if (is_invisible_nodata(grid->grid_data[i][j])) {
                 writeNodataValue(outrast, j, type);
             }
@@ -705,14 +714,19 @@ void save_vis_elev_to_GRASS(Grid *visgrid, char *elevfname, char *visfname,
     visrast = Rast_allocate_buf(elev_data_type);
     assert(visrast);
 
+    int nrows = Rast_window_rows();
+    int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
+
     dimensionType i, j;
     double elev = 0, viewshed_value;
 
-    for (i = 0; i < Rast_window_rows(); i++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
         /* get the row from elevation */
         Rast_get_row(elevfd, elevrast, i, elev_data_type);
 
-        for (j = 0; j < Rast_window_cols(); j++) {
+        for (j = 0; j < (dimensionType)ncols; j++) {
 
             /* read the current elevation value */
             int isNull = 0;
@@ -840,10 +854,15 @@ void save_io_visibilitygrid_to_GRASS(IOVisibilityGrid *visgrid, char *fname,
         counter++;
     }
 
+    int nrows = Rast_window_rows();
+    int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
+
     dimensionType i, j;
 
-    for (i = 0; i < Rast_window_rows(); i++) {
-        for (j = 0; j < Rast_window_cols(); j++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
+        for (j = 0; j < (dimensionType)ncols; j++) {
 
             if (curResult->row == i && curResult->col == j) {
                 /*cell is recodred in the visibility stream: it must be
@@ -940,8 +959,12 @@ void save_io_vis_and_elev_to_GRASS(IOVisibilityGrid *visgrid, char *elevfname,
 
     dimensionType i, j;
     double elev = 0;
+    int nrows = Rast_window_rows();
+    int ncols = Rast_window_cols();
+    if (nrows > maxDimension || ncols > maxDimension)
+        G_fatal_error(_("Grid size exceeds max dimension: %d"), maxDimension);
 
-    for (i = 0; i < Rast_window_rows(); i++) {
+    for (i = 0; i < (dimensionType)nrows; i++) {
 
         Rast_get_row(elevfd, elevrast, i, elev_data_type);